"If you asked a local this time last year they might have told you there were no longer any koalas in the Blue Mountains. However during the recent bushfires koalas have appeared on the edges of urban areas, including three koalas coming out of the bush to sit in buckets of water near the Springwood fire," said Dr Leigh.

"The fires would have forced koalas to move out of their normal home ranges and habitats, and this movement is taking them into developed areas where they are being seen by people. Unfortunately koalas are vulnerable to both fire and heat so the bushfires and extreme weather are likely to have had an impact on them. However the exciting thing is that we were not sure that koalas still existed in many of these areas."

Although koalas are not normally seen on the high altitude ridgelines in the Blue Mountains, they used to be abundant in the valleys either side. There are historical records advertising koala hunting opportunities in the Megalong Valley, back in the days of the koala fur trade. Since then koala numbers have dropped dramatically.

Dr Leigh says it's critical to find what is left of our koalas after such a massive drop in numbers. "Many Sydneysiders don't realise we still have koala populations around, in areas such as Campbelltown, and west right through to Bathurst. Even more people are not aware that koalas in NSW are now federally listed as vulnerable to extinction. Koalas are picky eaters and adapt to their local habitats, so if we're going to hang on to this iconic species we need to find and conserve all the surviving koala populations."

The recent Great Koala Count run by the National Parks Association of NSW has shown the power of citizen science for finding koalas, with 900 koalas reported throughout NSW and beyond. However the next step of assessing low density populations in rugged terrain is more challenging.

The information being collected is part of a larger national scale koala study led by the University of Sydney together with researchers from James Cook University and San Diego Zoo Global. The project is using new technology whole-genome DNA to prioritise koala populations for conservation management, right across the species range.

Dr Kellie Leigh is also director of Science for Wildlife Inc, a research partner with the University of Sydney that will undertake the regional koala mapping using innovative research methods such as a koala detection dog. The resulting data will be used in the University's genome research.

Koalas in the Blue Mountains are thought to be particularly important for conservation of the species due high levels of genetic diversity, and the large World Heritage Area might be an important habitat refuge for other populations under pressure from climate change. There is also a need to understand more about the impacts of bushfires on koalas in different habitats, which is even more urgent since the Blue Mountains bushfires.

If you know of any recent koala sightings in the Sydney basin or Blue Mountains please report the information to kellie.leigh@sydney.edu.au